This entry represents a conserved domain found in stromal antigen or stromalin proteins, also known as cohesin subunit SA-1/2/3 (STAG1-3 or SCC3 homologue 1-3) that were originally identified from a murine bone marrow stromal cell line and are represented in several organisms from yeast to humans. The homologues from yeast are cohesin subunit SCC3 and meiotic recombination protein Rec11. STAG1-3 and SCC3 are components of the cohesin complex, which is required for the cohesion of sister chromatids after DNA replication [1-3]. This domain consists of HEAT-like repeated helices [3]. Mutations in STAG3 have been associated with male infertility [4].

1: Cohesins are required for meiotic DNA breakage and recombination in Schizosaccharomyces pombe. Ellermeier C, Smith GR; Proc Natl Acad Sci U S A 2005;102:10952-10957. PMID:16043696

2: STAG3, a novel gene encoding a protein involved in meiotic chromosome pairing and location of STAG3-related genes flanking the Williams-Beuren syndrome deletion. Pezzi N, Prieto I, Kremer L, Perez Jurado LA, Valero C, Del Mazo J, Martinez-A C, Barbero JL; FASEB J. 2000;14:581-592. PMID:10698974

3: Structure and function of cohesin's Scc3/SA regulatory subunit. Roig MB, Lowe J, Chan KL, Beckouet F, Metson J, Nasmyth K; FEBS Lett. 2014;588:3692-3702. PMID:25171859

4: Mutations in the stromal antigen 3 (STAG3) gene cause male infertility due to meiotic arrest. van der Bijl N, Ropke A, Biswas U, Woste M, Jessberger R, Kliesch S, Friedrich C, Tuttelmann F; Hum Reprod. 2019;34:2112-2119. PMID:31682730